Definition, classification and evaluation of benign tumours ofthe jaw

Definition, classification and evaluation of benign tumours ofthe jaw

1. Definition, classification and evaluation of benign jaw tumours -DR. ZEESHAN ARIF

2. Contents Introduction Definition Classifications Evaluation Clinical examination Distribution Location Surface consistency Radiographical considerations Management

3. Introduction Tumours or neoplasms are new growths of abnormal tissue in the body. They are broadly divided into two groups – benign and malignant A benign tumour grows slowly and is usually encapsulated and it enlarges by peripheral expansion, pushes away the adjoining structures and exhibits no metastasis, however it may be locally aggressive. A malignant tumour, rapidly infiltrates the surrounding tissues, including vital structures and endangers the life of its host. It also shows metastasis in the distant parts of the body usually through lymph and blood streams.

4. The tissues involved in odontogenesis are Enamel organ Dental papilla Dental follicle Enamel organ is an epithelial structure derived from oral ectoderm Dental papilla and dental follicle : they are considered ectomesenchymal in nature because they are derived from neural crest cells.

5. The benign jaw tumours are divided into two broad categories— i . Odontogenic tumours ii. Non-odontogenic tumours. The human odontogenic structures are formed by the inductive interactions between epithelium and mesenchyme. The formation of these structures begin during 5th and 6th week of intrauterine life and continues till about 16th year after birth. During this long period, there is always a possibility of odontogenic lesions developing from these tissues; resulting in the development of malformations, hamartomas and neoplasms.

6. A malformation—is not neoplastic, but it can cause a functional or esthetic problem, because of its size or anatomical site. A hamartoma—is a benign lesion composed of a new growth of mature cells on existing blood vessels. (A lesion resulting from faulty development of the embryo). A benign odontogenic cyst or self limiting tumour may show an aggressive or malignant transformation. Management of such a lesion is always surgical.

7. Definition Embryologic events that initiate and control formation of human odontogenic structures through a finely regulated series of inductive interaction between epithelium and ectomesenchyme and failure of this inductive mechanism results in the formation of hamartomas malformations and neoplasms, collective known as odontogenic tumors.

8. Classification In 1946, Thoma and Goldman, described a classification of odontogenic tumours, based on the tissue cell of origin. It described the induction effects of one tissue (epithelium) on another (mesenchyme) in the pathogenesis of odontogenic tumours. They put these tumours into 3 broad groups: i . The lesions primarily derived from epithelium ii. Those originated predominantly from mesenchyme iii. A mixed group – both epithelial and mesenchymal tissue

9. Classification of odontogenic tumours ( Gorlin , Chaudhry, Pindborg – 1961) 1. Epithelial odontogenic tumours A. Minimal inductive change in connective tissue (Ectodermal origin) 1. Ameloblastoma 2. Adenomatoid odontogenic tumour 3. Calcifying epithelial odotogenic tumour – CEOT B. Marked inductive change in connective tissue (Mixed origin) 1. Ameloblastic fibroma 2. Ameloblastic odontoma 3. Odontoma 4. Complex odontoma 5. Compound odontoma

10. 2. Mesodermal odontogenic tumours 1. Odontogenic myxoma 2. Odontogenic fibroma 3. Cementoma a. Periapical cemental dysplasia (PCD) b. Benign cementoblastoma c. Cementifying fibroma d. Familial multiple ( gigantiform ) cementoma (Florid osseous dysplasia – FOD)

11. Kramer, Pindborg , Shear in 1992, revised the classification of odontogenic tumours (WHO). This classification is based on embryologic principles, that is, the embryonal inductive influence that the cells of one tissue exert upon the cells of another tissue. In the odontogenic tumours, the tissues are either derived from the ectoderm, namely the enamel organ or the mesenchyme proper (mesoderm). The ectomesenchyme is derived from cells of the neural crest during an early phase in embryogenesis.

12. Classification of benign odontogenic tumours (Kramer, Pindborg , Shear – 1992) Odontogenic epithelium without odontogenic ectomesenchyme 1. Ameloblastoma 2. Calcifying epithelial odontogenic tumour –CEOT. Pindborg tumour 3. Clear cell odontogenic tumour 4. Squamous odontogenic tumour B. Odontogenic epithelium with odontogenic ectomesenchyme , with or without dental hard tissue formation 1. Ameloblastic fibroma 2. Ameloblastic fibrodentinoma ( dentinoma ) 3. Odontoameloblastoma 4 Adenomatoid odontogenic tumour (AOT) 5. Complex odontome 6. Compound odontome

13. C. Odontogenic ectomesenchyme with or without inclusion of odontogenic epithelium 1. Odontogenic fibroma 2. Myxoma (odontogenic myxoma , myxofibroma ) 3. Benign cementoblastoma (true cementoma )

14. Non-odontogenic tumours and fibro-osseous lesions of the jaw bones Non-odontogenic tumours 1. Central fibroma 2. Myxofibroma 3. Ossifying fibroma 4. Osteoma 5. Osteoid osteoma 6. Benign osteoblastoma 7. Chondroma 8. Giant cell granuloma 9. Central haemangioma 10. Benign tumours of nerve tissue

15. Fibro-osseous lesions 1. Fibrous dysplasia of bone 2. Cherubism (Inherited fibro-osseous bone disease) 3. Ossifying fibroma 4. Central giant cell granuloma

16. WHO classification of non-odontogenic tumours of the jaws (Kramer, Pindborg , Shear (1992)) I. Osteogenic neoplasms Cemento -ossifying fibroma II. Non-neoplastic bone lesions 1. Fibrous dysplasia of the jaws 2. Cemento -osseous dysplasiasa . a.Periapical cemento -osseous dysplasia b. Focal cemento -osseous dysplasia c. Florid cemento -osseous dysplasia ( gigantiform ) III. Other cemento -osseous dysplasias a. Cherubism b. Central giant cell granuloma

17. Tumors of odontogenic epithelium without odontogenic ectomesenchyme Tumors of odontogenic epithelium with odontogenic ectomesenchyme Tumors of odontogenic ectomesenchyme with or without included odontogenic epithelium Ameloblastoma Ameloblastic fibroma Odontogenic fibroma Calcifying epithelial odontogenic tumor Ameloblastic fibro-odontoma Myxoma Squamous odontogenic tumor Odontoameloblastoma Cementoblastoma Clear cell odontogenic tumor Adenomatoid odontogenic tumor Complex odontoma Compound odontoma Daniel M. Lasken – Oral and maxillofacial surgery, Vol. 2.

18. ECOTDERMAL ORIGIN MESODERMAL ORIGIN MIXED ORIGIN (ECTO+MESO ) Amelo blastoma Odontogenic myxoma Ameloblastic fibroma Adenomatoid odontogenic tumor Central odontogenic fibroma Ameloblastic fibro-odontoma Cementomas- -periapical cemental dysplaisa Odontomas - Calcifying epithelial odontogenic tumor (pindborg tumor) -familial multiple gigantiform cementoma - Complex Squmaous odontogenic tumor -cementofying fibroma -compound Clear cell odontogenic tumor -Cementoblastoma Calcifying odontogenic cyst Burket – histopathological classification

19. WHO histological classification 2005 Benign tumors Odontogenic epithelium with mature, fibrous stroma without ectomesenchyme Ameloblastoma Solid/ multicystic Extraosseous /peripheral Desmoplastic Unicystic Squamous odontogenic tumor Calcifying epithelial odontogenic tumor Adenomatoid odontogenic tumor Keratocystic odontogenic tumor

20. Odontogenic epithelium with odontogenic ectomesenchyme with/without hard tissue Ameloblastic fibroma Ameloblastic fibrodentinoma Ameloblastic fibro- odontoma Odontoma Complex Compound Odontoameloblastoma Calcifying cystic odontogenic tumor Dentinogenic ghost cell tumor

21. Mesenchyme and/or odontogenic ectomesenchyme with/without odontogenic epithelium Odontogenic fibroma Odontogenic myxoma / myxofibroma Cementoblastoma Bone-related lesions Ossifying fibroma Fibrous dysplasia Osseous dysplasia Central giant cell granuloma Cherubism Aneurysmal bone cyst Simple bone cyst

22. Malignant tumors a)Odontogenic carcinomas 1 Metastasizing ameloblastoma 2 Ameloblastic carcinoma Primary Secondary (dedifferentiated) intraosseous Secondary (dedifferentiated) peripheral 3 Primary intraosseous squamous cell carcinoma Solid type From KOT From odontogenic cysts 4 Clear cell odontogenic carcinoma 5 Ghost cell odontogenic carcinoma b)Odontogenic sarcomas Ameloblastic fibrosarcomas Ameloblastic fibrodentino -and fibro- odontosarcoma

23. Evaluaion

24. EXAMINATION AND DIAGNOSTIC METHODS Lesions of the oral cavity and perioral areas must be identified and accurately diagnosed so that appropriate therapy can eliminate the lesions. When abnormal tissue growth is discovered, several important and orderly steps should be undertaken to identify and characterize it. When the dentist discovers or confirms the presence of a lesion, the information must be discussed with the patient in a sensitive manner that conveys the importance of urgent attention to the problem without alarming the patient.

25. History of the Specific Lesion Prolonged duration → may be congenital Long duration without pain → benign neoplasm Short duration, rapid growth→ malignant growth Mode of onset and progress History of trauma may be obtained in many bone lesions like osteogenic sarcoma. Spontaneous swelling and rapid growing lesion may be malignant, while very slowly growing lesion may be benign growth.

26. Exact site and shape Progress of the lesion - Whether the swelling has been growing slowly or it has remained stationary for a long time (benign growth). Has it been growing again after a stationary period of months/years (malignant transformation in a benign lesion) or has it been continuously increasing in size (malignant growth)? Change in character of a lesion Whether there are ulcerations over the lesions? Fluctuation, softening, etc. are noticed by the patient recently? Whether painless swelling has become painful – secondary infection may have set in the lesion.

27. Associated symptoms Pain, abnormal sensations, anaesthesia, paraesthesia over a region, dysphasia, nasal obstruction – breathing difficulty, tenderness, lymphadenopathy. Trismus Loss of body weight Malignant growth Recurrance Habits

28. Clinical Examination of the Lesion

29. General considerations These tumors usually are painless and most of them do not metastasize unless they are malignant and are not life threatening unless they interfere with a vital organ by direct extension. They represent a new un co-ordinated growth Few spread by direct extension and few by metastases when they turn malignant. Odontogenic tumours are detected usually by enlargement of jaws or are found during radiographic examination They tend to resemble the tissue of origin histologically They are insidious on onset and grow slowly

30. OT are generally slow by formation of additional internal tissue because of this the radiographic borders of benign tumors appear relatively smooth, well defined , sometimes corticated OT have more of female predilection with 1:3 of male : female ratio Age distribution is according to the type of odontogenic tumour roughly includes 1 st to 7 th decade of life

31. Distribution

32. < 30 years

33. > 30 years

34. > 40 years

35. Location Site of the tumor is of striking importance when it comes diagnosis of OT Most of the odontogenic tumors are found in maxilla than that in the mandible

36. In the mandible

37. Molar and ramus region

38. Surface consistency Smooth - Benign and malignant mesenchymal origin Differential diagnosis Cysts Space abscess Benign minor salivary glands Traumatized lesions Retention cyst

39. Palpation

40. Bony hard consistency

41. Pain The clinical features of most benign odontogenic tumours are nonspecific Benign odontogenic tumours show slow expansive growth with no or slight pain In contrast, pain is the first and most common symptom followed by rapidly developing swelling in nearly all malignant odontogenic tumors.

42. Differential diagnosis

43. Radiographic considerations position size shape presence or absence of lesional calcifications estimation of soft tis­sue volume in relation to calcified tissue cyst formation impingement on or inclusion of vital anatomic structures, displacement of teeth or root resorption boundaries between lesion and bone

44. Radiographic examination a cyst usually appears as a radiolucency with sharp borders

45. a radiolucency with ragged, irregular borders might indicate a malignant or more aggressive lesion

46. General radiographic features Benign lesions : Often encapsulate. Gradual enlargement. Hence tumor borders are usually smooth and Radiographically well defined. Effect on adjacent tissues – benign tumor exerts pressure resulting in displacement of teeth or bony cortices. Root resorption – benign tumors – resorption of teeth in a smooth fashion and any along the adjacent edge of tumor. Malignant tumors – surround entire root if resorption occurs –some times no resorption.

47. Odontogenic tumors may be : - Radiolucent - Mixed radiolucent and radiopaque - Radiopaque

48. Root resorption displacement non-vital tooth AOT Central Giant Cellgranuloma Granuloma Odontogenic myxoma Odontgenic carcinoma Odontoma Ameloblastoma Keratocystic odontogenic tumor Dentinogenic ghost cell tumor

49. Infiltration into bone

50. Tumor encapsulation

51. Pathological Radiolucency- Contacting tooth

52. Radiolucencies - not contacting teeth

53. Radio-opacities Solitary radiopacities not contacting tooth are True intra bony radiopacities : a. Tori. b. Unerupted , impacted & supernumerary teeth c. Retained roots d. Focal & diffuse sclerosing osteomyelitis

54. Biopsy Definitive diagnosis is established after incision, excision or intraoperative (frozen section) biopsy Biopsy technique is selected after careful assessment of patient & of use of local, sedation or GA Excisional biopsy is performed for completely calcified lesions Intraoperative frozen sections is used to study questionable soft tissue

55. Management Goals of treatment Eradication of lesion with the least morbidity, preservation and restoration of function. Depends on Growth potential Size Anatomic location Association with vital structures Soft tissue involvement

56. Surgical treatment Curettage Cautery (electrocoagulation) Enbloc resection Resection with continuity defect Partial resection Total resection Reconstruction with bone grafting or appropriate free tissue transfer

57. References Burket’s - Oral medicine diagnosis and treatment. Wood and goaz - Differential diagnosis of oral and maxillofacial lesions Daniel M. Lasken – Oral and maxillofacial surgery, Vol. 2. James R. Hupp – Contemporary oral and maxillofacial surgery, 6 th edition Kruger – Text book of oral and maxillofacial surgery Contemporary oral and maxillofacial surgery – Neelima Malik